Study Finds Long-Term Heavy Cannabis Use May Impair Driving

Long-term, heavy cannabis use might be making adults bad drivers. Especially, according to a new study in Drug and Alcohol Dependence, if drivers started consuming cannabis in their early teens. Researchers studying the impacts of recreational cannabis consumption on cognitive function say bad driving behaviors like speeding, ignoring traffic signals, and getting into accidents could stem from heavy adolescent cannabis use. Furthermore, researchers found that long-term cannabis users drove badly whether or not they were under the influence of THC.

Dr. Staci Gruber is an Associate Professor of Psychiatry at Harvard Medical School and the Director of the Cognitive and Clinical Neuroimaging Core at McLean Hospital’s Brain Imaging Center. She’s an expert in the ways that substance use among adults and adolescents affects the brain, and her recent work looks at how cannabis affects cognitive ability and brain development. Her latest study, “Recreational cannabis use impairs driving performance in the absence of acute intoxication,” presents a new perspective on the relationship between cannabis and traffic safety.

No, this isn’t a study showing how being high makes you a bad driver. In fact, many studies that have looked into